Priority is claimed per 35 USC 119 under French application serial number 9912754 Filed Oct. 13, 1999.
The present invention relates to a cable reel and to an electromagnetic wave communication device equipped with such a reel.
A device (such as an antenna) intended for communication, based on electromagnetic signals, with satellites movable in the terrestrial reference system comprises, in general terms, at least one first and one second component movable in rotation relative to one another (pivot connection). It is necessary, at this pivot connection, to ensure the continuity of the electrical signals carried by various cables (information transmission, supply or command signals).
A conventional solution for ensuring such continuity involves using rotating contacts. However, this solution has a high cost and proves relatively uncertain as regards operating reliability.
In order to overcome these disadvantages, the invention provides a reel which comprises a first component movable in rotation in relation to a second component about an axis and at least one first cable fixed to the first component at at least one point, in which the first cable is fixed to the second component at at least one point and in which the first cable is wound spirally about the axis.
The first cable ensures the transmission of the information in one direction; in order to make it possible to transmit the information in the opposite direction, the reel comprises at least one second cable wound spirally about the axis and separated from the first cable by a first flange perpendicular to the axis.
It is also proposed that the first flange comprise a hole for the passage of the second cable and be fixed to the second component. Thus, it is not necessary for the second component to form a guide for the second cable at the height (along the axis) of the spirals formed by the first and second cables. With the dimensions of the system being constant, this makes it possible to increase the ratio of the outer radius to the inner radius of the spiral and therefore to increase the possibility of relative rotation of the first and second components.
The first cable is received in a first magazine delimited axially by a second flange and by the first flange. The second cable is received in a second magazine delimited axially by the first flange and by the first component. A third cable is received in a third magazine delimited axially by the second flange and by the second component.
The first magazine and the second magazine are delimited radially by the first component, on the one if hand, and by the second component, on the other hand. The third magazine is delimited radially by a wall emanating from the second flange, on the one hand, and by the second component, on the other hand. The second flange is fixed to the second component.
The invention also provides a device for electromagnetic wave communication, comprising at least one transmitter/receiver assembly connected mechanically and electrically to a plinth, and also such a reel.